Host cell surface oligosaccharides serve as receptor ligands for protein molecules such as enzymes, antibodies and lectins, and they initiate many critical biological reactions. Unfortunately, these receptor ligands also initiate many harmful biological reactions by providing attachment sites for viruses, toxins, bacteria, etc.
Normally in an oligosaccharide, the constituent monosaccharide groups are linked by ether oxygen linkages. This ether oxygen linkage is difficult to construct chemically. Linking methods are specific for each sugar employed. The ether oxygen linking group is susceptible to hydrolysis by glycosyl hydrolases and non-enzymatic chemical hydrolysis. This ease of hydrolysis makes it difficult to use carbohydrate structures as pharmaceuticals. Further, there are no known methods of automated syntheses for complex oxygen ether linked carbohydrates.
The present invention provides saccharide compounds wherein the linkage is less susceptible to hydrolysis and methods for their preparation.